Papers by Keyword: Assembly

Abstract: The global competitive situation and change to customer market results in shorter product life cycles and high variant diversity as a consequence of customization. Especially in assembly systems the increasing complexity forces manufacturing companies to enhance their flexibility. In manual assembly systems the worker and the use of his cognitive skills provide the required flexibility and knowledge to perform the assembly process efficiently. The presented approach deals with an integrated technology management concept for manual assembly. Thereby, a special focus is set on support technologies which are aimed to support the cognitive skills of the worker. In the first step useful technologies have to be identified on the base of a specific search strategy. As soon as a potential technology is identified, the technology investigation starts. Core element in the concept is an impact analysis to assess the benefit of new support technologies in a specific manual assembly system.

Abstract: An important task of designing the robotic assembly stand is to ensure the reliability and accuracy of the parts mating process. This can be achieved by selection of the appropriate method of assembling and by providing the required accuracy of the devices in the kinematic chain of assembly operation. Using high accuracy equipment and instrumentation leads to an increasing of the probability of correct realization of the process of parts mating, but this greatly increases the cost of assembly stand. The use of too precise and complex equipment to robotize the assembly process can be highly uneconomical. This paper presents a mathematical model that allows the selection of the parameters of the modular assembly robot performing the process of mating parts with flat and cylindrical surfaces, which represent the largest share among all the assembled parts. The presented model allows for the optimal selection of the accuracy of each robot modules which ensures reliable realization of assembly process without unnecessary increasing their accuracy, and therefore the stand cost. In the final part of the paper, the results of the model solution have been presented.

Abstract: A system to monitor the signal produced by surface plasmon resonance (SPR) has been designed and tested. The built-in sensor consists of a polarized light source having a wave length 840 nm and a built in 128 photodiodes constructed around the maximum SPR angle to detect the reflection light from the gold surface. The signal produced from the diodes is then amplified and digitized. We use 5173 Hz clock to sample the signal generated by the diode array pixel during the reflection process producing SPR signal around the maximum angle. We program Arduino Mega 2560 to process the signals and transfer it using Lab View to present the data versus sampling time. Doing this, we can record the SPR signal versus time, known as the SPR dynamic signal. To test the performance of the system and to know the properties of the SPR signal, we test the system using ethyl alcohol with concentration of 10% (v/v) up to 90% (v/v). The result shows that the system can be used to monitor the dynamics of SPR signal during the reaction process and it indicates the possibility of using the instrument to detect various kinds of SPR signal related to the chemical and or biological process in the samples.

Abstract: The paper discusses the problems on accurate assembly of large-sized cylinder segments by illustrating an example of the geokhod assembly. The mathematical expressions for determining deviations of sector profile from the nominal circle of the shell depending on the radius of sector, its tolerances and the location of supports. The influence of the distance between the supports on the profile deviation is shown. Solutions to minimize the profile deviation are given.

Abstract: In the paper we propose an approximation model of the measured point cloud for machined cylindrical surfaces. The developed model is different from the traditional view because it relies on the contact of mating surfaces. The model allows to determine the parameters of cylindrical surfaces such as the coordinates of the center and the radius. To evaluate the geometrical parameters of the model the objective function is formulated, which characterizes the nature of the interface and a number of limitations. The approximation problem is solved by use of nonlinear optimization methods. The model takes into account the surfaces contact, which influences in deformation of its irregularities. The irregularities it is form deviations and surface roughness. The application of the model on the example of the shaft coupling with the inner ring of the bearing. There is given an estimate of geometric parameters for interfacing compared to method of least squares, which is widely used for coordinate measurements. As a result of research it was obtained that the proposed method can predict more accurately the parameters, which describe the location of the cylindrical surfaces made during assembly.

Abstract: In this contribution is presented application of evolution diagrams at the assembly process of at the intelligent manufacturing and assembly cell. At this assembly cell was designed new assembly configuration for next research to our department and institute. Intelligent manufacturing and assembly cell is situated at the Institute of Production Systems and Applied Mechanics. The complex design of assembly sequences at the intelligent manufacturing and assembly cell is realized on the basis of evolution diagrams and outgoing from knowledge about intelligent manufacturing and assembly systems. For intelligence increase of assembly process was this cell completed by additional sensors. This assembly process is possible to name intelligent assembly process.

Abstract: The influence of the state of assembly and entity on modal simulation data in the computer simulation is different. In this paper, a typical modal analysis of hydraulic manipulator with the finite element method is conducted to discuss the different. The assembly is assembled by Boolean operations to makes surfaces merging together directly and then converted into the solid model. This way can ensure the validity of the comparable data. The conclusion shows that properly setting the assembly model can make the simulation results closer to the actual working conditions in the computer simulation by comparing the modal simulation data.

Abstract: This paper presents a methodology for the simulation and optimization in a virtual environment of a manual assembly process. For validation of the methodology the authors chose an assembly process that is already used in the manufacturing industry. In the first step of the proposed methodology the existing process is simulated and then based on the simulation the activities and equipment involved are being analyzed and in the next step the assembly process is to be optimized using simulation and a series of modification vectors such as: layout, devices, tools and movement sequences. The case study presented in the paper aims to optimize the assembly process of a pneumatic actuator of a butterfly type valve.

Abstract: The paper presents the task scheduling issue, which main aim is to establish a proper sequence of tasks, that would maximize the utilization of companys production capacity. According to the literature sources, the presented sequencing problem, denoted as CSP (Car Sequencing Problem) belongs to the NP-hard class, as has been proven by simple reduction from Hamiltonians Path problem. Optimal method of solution has not yet been found, only approximate solutions have been offered, especially from the range of evolutionary algorithms. Regardless of specific production system, while considering reception of new tasks into the system, current review of the state of the system is required in order to decide whether and when a new order can be accepted for execution. In this paper, the problem of task scheduling is limited to the specific existing mixed-model production system. The main goal is to determine the effective method of creation of task sequence. Through the use of computational algorithms, and automatic analysis of the resulting sequence, rates of production are able to be checked in a real time, and so improvements can be proposed and implemented.

Abstract: Liquid crystal was formed in a ternary system of tetraethylene glycol lauryl ether, water and 1-ethyl-3-methylimidazolium hexafluorophosphate. Its structure was identified by polarized optical microscopy and small-angle X-ray scattering techniques. Compared to that in the binary system, lamellar phase was retained with the addition of a small amount of imidazolium salt. Molecules of 1-ethyl-3-methylimidazolium hexafluorophosphate were considered to be solubilized in the polar domain of the ordered assemblies. Results on their influence on the lamellar phase enlighten the use of imidazolium salts to modulate liquid crystalline materials and other assemblies.